Question

The following table shows the number of students of class X and the time they utilized daily for their studies. Find the mean time spent by 50 students for their studies by direct method:

Time (hrs)	No. of students
0 − 2	7
2 − 4	18
4 − 6	12
6 − 8	10
8 − 10	3

Answer 1

Time (hrs)	Class mark xi	Frequency (Number of students) fi	Class marks × frequency xifi
0 − 2	1	7	7
2 − 4	3	18	54
4 − 6	5	12	60
6 − 8	7	10	70
8 − 10	9	3	27
Total		∑fi = 50	∑xifi = 218

Mean `(bar X) = (sum f_ix_i)/(sum fi)`

= `218/50`

∴ `bar X = 4.36`

∴ The mean time spent by students is 4.36 hours.